Inflammatory bowel disease (IBD) is the general term used for a heterogeneous group of intestinal
disorders, including Crohn’s disease (CD) and ulcerative colitis (UC). Questions are raised about the
value of serological markers such as anti-Saccharomyces cerevisiae antibodies (ASCA) IgG and atypical
perinuclear antineutrophilic cytoplasmic antibody (atypical pANCA) in the diagnosis and differentiation of
CD and UC. ASCA Immunoglobulin A (IgA) antibody is said to have clinical utility in diagnosing IBD,
specifically in ASCA IgG-negative CD patients. Aim of Work: The aim of this study was to determine if
these markers can replace ordinary invasive methods for diagnosis and classification of IBD and whether
they have predictive role in prognosis of IBD. Subjects and Methods: 57 subjects (45 patients and 12
controls) were included in this study. Patients were subjected to full history taking, thorough medical
examination, radiological, endoscopic and histopathological examination. 5ml of blood were retrieved
from all subjects and assayed by Enzyme Linked Immunosorbent Assay (ELISA) for quantitative
measurement of ASCA (IgG and IgA) and pANCA. Results: There was significant increase in ASCA IgG
and IgA in CD patients and pANCA in UC patients when compared with control subjects. Sensitivity ,
specificity , positive predictive value (PPV) and negative predictive value (NPV) of ASCA IgG , IgA in CD
and pANCA in UC when compared with controls were (50, 86.3, 85.7, 25%), (25.5, 66.67, 75, 18.18%)
,and (50, 66.67, 75, 40%) respectively . While ASCA+ve / pANCA-ve combination for CD, and ASCA-ve /
pANCA+ve for UC had sensitivity, specificity, PPV and NPV of (34.6, 100, 100, 26.09%) and (33.33, 100,
100, 42.86%) respectively. ASCA IgG was elevated in penetrating and structuring type of CD and more in
proximal colitis than distal parts .Conclusion: ASCA (IgG and IgA) and pANCA are useful tools for
diagnosis and classification of IBDs if used in combination , but not alone .
Key Words: ASCA (Anti-Saccharomyces cerevisiae antibody) – pANCA perinuclear antineutrophilic
cytoplasmic antibody – IBD (Irritable bowel disease) – Crohn’s disease – Ulcerative colitis. |
